# CVE-2026-46022: misc: ibmasm: fix OOB MMIO read in ibmasm_handle_mouse_interrupt()

CVE-2026-46022 is fixed in linux on 1 platform, first by DEBIAN-CVE-2026-46022, released May 27, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-46022
- Priority: High
- CVSS: 7.1 (Moderate)
- EPSS: 0.0015
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: May 27, 2026
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-46022

## Description

In the Linux kernel, the following vulnerability has been resolved:  misc: ibmasm: fix OOB MMIO read in ibmasm_handle_mouse_interrupt()  ibmasm_handle_mouse_interrupt() performs an out-of-bounds MMIO read when the queue reader or writer index from hardware exceeds REMOTE_QUEUE_SIZE (60).  A compromised service processor can trigger this by writing an out-of-range value to the reader or writer MMIO register before asserting an interrupt. Since writer is re-read from hardware on every loop iteration, it can also be set to an out-of-range value after the loop has already started.  The root cause is that get_queue_reader() and get_queue_writer() return raw readl() values that are passed directly into get_queue_entry(), which computes:    queue_begin + reader * sizeof(struct remote_input)  with no bounds check. This unchecked MMIO address is then passed to memcpy_fromio(), reading 8 bytes from unintended device registers. For sufficiently large values the address falls outside the PCI BAR mapping entirely, triggering a machine check exception.  Fix by checking both indices against REMOTE_QUEUE_SIZE at the top of the loop body, before any call to get_queue_entry(). On an out-of-range value, reset the reader register to 0 via set_queue_reader() before breaking, so that normal queue operation can resume if the corrupted hardware state is transient.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 12.15 (bookworm) | 6.1.176-1 | [DEBIAN-CVE-2026-46022](https://patchblox.com/security/data/fix/linux/debian-cve-2026-46022.md) | May 27, 2026 |
| Linux | linux Debian 13.5 (trixie) | 6.12.86-1 | [DEBIAN-CVE-2026-46022](https://patchblox.com/security/data/fix/linux/debian-cve-2026-46022.md) | May 27, 2026 |
| Linux | linux Debian 14 | 7.0.4-1 | [DEBIAN-CVE-2026-46022](https://patchblox.com/security/data/fix/linux/debian-cve-2026-46022.md) | May 27, 2026 |

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Data as of 2026-11-08T06:59:42Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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